In West Sangilen (South-East Tuva, Russia), there are outcrops of metamorphic and magmatic complexes of early Caledonides, which are related to the period of long-term collisional and post-collisional events in the northwestern edge of the Tuva-Mongolian massif. The evolution of orogenic structures in West Sangilen is an example of the collapse of folded structures in case of changes in tectonic regimes from compression and transpression (collision period) to intra-and marginal continental transform-shear extension (post-collision period). Numerous geologic features give evidence of changes in the kinematics and characteristics of deformations, as well as in the conditions of metamorphism and magmatism in the study region. However, thinning of the crust during the collapse of the collisional orogenic structure has not been supported by any direct data. Indicators of such events are the complexes of combined dykes, which are abundant in West Sangilen, especially in the area between the Erzin and Naryn rivers and on the right bank of the Erzin river. The most representative object is a combined basite-granite dyke at the foot of the Tavit-Dag mountain. Its position is controlled by the strike-slip fault system. The thermochronological analysis of mingling rocks shows different ages of the closure of isotope systems: 494.8±5.4 Ma (U/Pb, zircon, basites), 489.7±7 Ma (U/Pb, zircon, granitoids), 471.2±1.9 Ma (Ar/Ar , amphibole, basites), and 462.5±1.0 Ma (Ar/Ar, biotite, basites). Taking into account the parameters of the closure of isotope systems (~800-900 °C, zircon, U/Pb; ~500 °C, amphibole, Ar/Ar; ~300 °C, biotite, Ar/Ar), the cooling curve of the mingling dyke is estimated. It corresponds to lowering of the temperature by 600 °C (900 °С  500 °С  300 °C) in the period from 500 (494.8±5.4) Ma to 461 (462.5±1.0) Ma. It is shown that the recent thermal events did not affect the mingling dyke located on the Tavit-Dag site. The sequential changes in the age of the closure of isotope systems are indicative of thinning of the crust in the study region P a l e o g e o d y n a m i c s RESEARCH ARTICLEFor citation: Vladimirov V.G., Karmysheva I.V., Yakovlev V.А., Travin А.V., Tsygankov А.А., Burmakina G.N., 2017. Thermochronology of mingling dykes in West Sangilen (South-East Tuva, Russia): evidence of the collapse of the collisional system in the north-western edge of the Tuva-Mongolia massif.

A new numerical model has been developed that makes it possible to describe the process of formation of a dyke of a combined composition on the basis of the dynamics of a viscous compressible fluid. The numerical thermo-mechanical model shows the processes of magma mingling and taking into account multiphase interaction of melts which are different in composition and properties. The models suggest a mechanism for uplifting of high-density mafic enclaves in a chamber/dyke filled with salic magma by gravitational floating in the enclosing granite magma that has been cooled and lost volatile components. The performed simulation shows that the main parameter controlling the shape and size of the ascending bodies is the difference in densities. The viscosity contrast determines whether interpenetration and hybridization of magmas occur. The limiting ratio of felsic material in the mixture, which is capable of uplifting denser mafic enclaves, is estimated. The duration of melt uplifting in combined dykes is estimated with respect to the viscosity parameters. At a typical rate of 2-3 km per year, it amounts to almost 12 months.

The regularities of thermocatalytic transformation of pine ethanol lignin in supercritical ethanol in the presence of catalysts NiCu/SiO₂ and NiCuMo/SiO2 in the temperature range 250–400 °C were established. The composition and structure of ethanol lignin, liquid and solid products of its conversion were studied by methods of elemental analysis and gel-permeating chromatography (GPC). The composition of gaseous products – by method of gas chromatography. At the process temperature of 250 °C the catalysts do not have a significant effect on conversion of ethanol lignin. The maximal yield of liquid products (83.5 wt. %) was obtained at temperature 300 °C in the presence of catalyst NiCuMo/SiO₂ containing 8.8 wt. % of molybdenum. At temperature 350 °C NiCu/SiO₂ and NiCuMo/SiO2 catalysts contribute to the almost complete conversion of ethanol lignin into liquid and gaseous products, and the yield of solid products does not exceed 1 wt. %. In liquid products of catalytic conversion there is a decrease in the atomic ratio of O/C and the increase of H/C atomic ratio as compared to initial ethanol lignin due to catalytic intensification of reactions of deoxygenation and hydrogenation of lignin and products of its depolymerization. According to GPC data on the curves of molecular mass distribution (MMD) of liquid products of thermocatalytic conversion of ethanol lignin at 300 °C there are peaks with highs at 160 and 380 Da, probably related to guiacyle monomers and dimmers, respectively. From the comparison of MMD of liquid products obtained by ethanol lignin depolymerization at 300 °C over catalysts NiCu/SiO₂ and NiCuMo/SiO₂ it follows, that the introduction of molybdenum in the catalyst promotes the formation of monomeric guaiacyl products

научно-исследовательский институт радиационной гигиены имени профессора П.В. Рамзаева, Федеральная служба по надзору в сфере защиты прав потребителей и благополучия человека, Санкт-Петербург, Россия 2 Федеральная служба по надзору в сфере защиты прав потребителей и благополучия человека, Москва, Россия Санитарно-эпидемиологический надзор 77 Радиационная гигиена Том 10 № 4, 2017 The average annual effective doses for the population of the settlements of the Russian Federation attributed to zones of radioactive contamination due to the Chernobyl accident (for the zonation purposes), 2017 gennadiy ya.

The purpose of the study was to study the patterns of forming average annual and cumulative exposure doses. The subject of the study was the dynamics of the average annual and cumulative doses of the adult population of the Russian Federation after the Chernobyl nuclear power plant accident. Results and conclusions. We estimated the contribution of external and internal exposure doses accumulated during the first year after the disaster into the total doses accumulated in 1986–2016 in the population living in the areas with different levels of 137Cs activity in surface soil. The contribution of the exposure doses received during the first year after the accident into the total doses accumulated in 1986–2016 by the population of the regions with different levels of 137Cs activity in surface soil was more than 30%. The contribution of the internal exposure dose received during the first year after the accident into the total exposure dose accumulated in 1986–2016 by the population exceeded that of the external dose. We predicted the average annual and cumulative exposure doses of the population until the year 2056: in 2016, the actual average annual exposure dose for the population exceeded 1.0 mSv/year only in 19 settlements of the Bryansk Region while by 2056 the number of such settlements would be null. In 2016, the average cumulative exposure dose of the population exceeded 70 mSv in 55 settlements of the Bryansk Region, the maximum being 299 mSv. According to the forecast for the year 2056, the total number of settlements in the Bryansk Region with the average cumulative exposure dose of the population equal to or greater than 70 mSv would approach 92. All these settlements are situated only in the Bryansk Region. The maximum expected value of the average cumulative exposure dose would be 374 mSv. We estimated the contribution of the population exposure dose accumulated in 1986–2016 into the exposure dose accumulated during 70 years (a lifetime dose). The contribution of the average accumulated effective exposure dose for 1986–2016 into the dose predicted for 1986–2056 ranged 86% to 94%. This means that the major part of the lifetime dose has been already accumulated by the locals